Vitodens 200 programmer.

I can't see any reason why not apart from a possible warranty issue. Can you get the connectors? If so, making up a lead would seem to be a good way, then if you have to put the thing back you can.

Screened cable would be a good idea in case of RF pickup, considering your location.

In message , "Dave Plowman (News)" writes

why DC ?

The Saunier Duval programmer is 24vdc powered, but almost every other one I've encountered is mains powered

In message , Andy Hall writes

It's probably a relay switching inside

I don't think RF would be a problem, but surely the manual will give an indication of what the timer does

L, N and two switch contacts would sound logical to me

It's basically just a PCB with surface mount components on it - no signs of mains transformers or relays etc anywhere.

I've not investigated fully but I'd guess it controls external relays etc via an external interface.

I have a spare programmer as I bought the external temperature compensation kit which uses a different one. Ie, different electronics etc but 'physically' the same. So I can trace what the four pin plug on the PCB is wired to at leisure

=A0 London SW

You need Part No. 7133 385 according to the installation manual. This is a wall mounting adaptor plate for the controller and includes a blanking plate for the front of the boiler.

Maximum cable length is 30M and you need 2 core cable apparently.

Steve

Ah. Thought I'd read it from cover to cover.

Wonder why the plug is 4 pin?

But thanks very much for that.

Mine's 0, 12v and then 2 way data on a single wire......

The controller handles time, signals temperature as an actual reading and allows control of the relative sensitivity of the room temperature vs. the weather compensator.

I wouldn't assume that in a boiler of this type....

In message , "Dave Plowman (News)" writes

Surely there's a schematic which explains it all

I wouldn't like to make any assumptions, especially as I don't know the beast, especially following the brief description, but even quite a lot of small, compact ones use a cap/resistor dropper from a mains supply.

"Data" also would be a very posh name for what is effectively a switch

I must look at it again more thoroughly but I remember it as not giving an actual circuit of everything - just those external parts like pump etc. More of a block schematic.

In message , "Dave Plowman (News)" writes

Well, of course it won't, but between what it does tell you (don't ignore the fault finding) and poking around with a meter, you should be able to crack it

Hmm.

It's definitely two wires according to the schematic. Pins 7&6 of connector X3.

See page 13 of this document:-

Steve

controller with the original still in place but set to continuous?

Yes - similar. It's called a Vitotronic 200 - the one with weather compensation mode.

Well, P11 shows quite clearly that there are two options one which is a radio clock (which is unlikely on one contained within the boiler itself as opposed to a remote) and one with live and neutral power lines where one of the switch contacts is that live line - what's the problem ?

No, I believe you remove the whole controller from the front of the boiler and relocated it - which is why the mounting kit I gave you the part number for earlier includes a blanking plate to fill the hole on the boiler

The external temperature sensor appears to connect to pin 1+2 on connector X3 and not directly to the the Vitotronic unit so it shouldn't make any difference.

I have every faith that if you just find pins 6+7 on connector X3, extend them to wherever you would like the control panel and reconnect them, it should work.

The official manufacturers part would be nice because it gives you a proper mounting but I can't see it being necessary from a technical point of view.

Steve

The weather compensation kit comes with a replacement 'programmer' so there must be more to it.

I'm just curious about why they'd combine the DC with the data when there's no need. And why the controller has a four pin connector.

The mounting and blank plate will certainly make things easy so I'll order it up tomorrow.

Spoke to Viessmann this morning - what a breath of fresh air getting straight through to a bloke who obviously knew the things inside out - when asking for technical advice.

The part number you gave is correct for earlier units but it seems can't be done with current ones. What they do supply is a slave unit which looks the same and duplicates all the operational features of the main one which stays in place - all it doesn't do is allow access to maintenance and setup codes/features.

It does indeed work on only two wires and it's a Vitotronic 300 with a part number 7248 907 - this is for the weather compensated one.

Good stuff. Is it expensive?

Steve